Above: Artist rendering 1I/’Oumuamua by M. Kornmesser, European Southern Observatory
DeepSpaceNews — It seems hard to believe that we only discovered the interstellar object (ISO) officially known as 11/’Oumuamua two months ago.
Initially designated as comet C/2017 U1 by the Minor Planet Center, it was first spotted on Oct. 18, 2017.
Astronomers first thought their new comet originated in the faraway Oort Cloud.
But when they gauged its speed as it zoomed along at perihelion distance, it was clear that this object didn’t behave like a comet at all. At 87.7 km/s, it was moving about 4.2 km/s too fast for it to be bound to the sun.
The object had to come from outside our own solar system to travel at such a speed, researchers realized. That could mean just one thing: The object was an interstellar object (ISO), and the first ISO ever observed.
Given that its very existence is so novel, the MPC had to designate it with the number “1” and give it the Hawaiian name, ‘Oumuamua, which means “first messenger” in Hawaiian.
Maybe 1I is a messenger from another star system, as some have suggested of late.
Barring that, the question is whether we can observe this ISO and figure it out where it actually came from and what it’s doing here now?
Let the race begin
Soon after ‘Oumuamua got its credentials as a bonafide ISO on Oct. 24, the race was on. Astronomers from all around the globe rushed to study ‘Oumuamua.
I was one of them. Within a day, my team here at The Asteroid Institute set out to obtain telescope data and study I1.
Within two days, my fellow researchers and I obtained director’s discretionary time on the Apache Point 3.5 m telescope in Sunspot, New Mexico.
That’s how we obtained images of the asteroid as it passed through the desert skies.
The last time a non-man made object was seen leaving our solar system was back in 1980. That was comet C/1980 E1 Bowell. However, C/1980 was not a true interstellar object because it originated inside our solar system and was thrown out of the confines of our Sun’s gravity by the strong gravitational influence of Jupiter.
Asteroids have been observed indirectly around other stars, but this was the first opportunity to study a piece from another solar system while it still was in the confines of ours at an unprecedented level of detail.
Photometric colors and spectra telling the chemical composition of the surface of 1I were taken, and study revealed that it has a reddish color and probably came from the inner part of its original system where its host star’s heat played an important role in the formation of asteroids and planets.
Additionally, the object’s rotation was studied revealing that the object was shaped like a skinny potato.
The image at right shows an asteroid with a similar shape to 1I/’Oumuamua.
It’s thought that objects that are elongated have plasticity and are shaped, stretched, and elongated when they encounter the gravity of a planet during a close approach.
Does this imply that 1I experienced a gravitationally stretching event before it was ejected from its solar system? Time can only tell as we gather more data.
My team and I have submitted our observations to The Astrophysical Journal Letters for publication of our results. Read it in full and in place below the fold, or access it here.
For DeepSpaceNews, I’m Bryce Bolin.
Here’s a video showing what ‘Oumuamua looks like spinning through space.
Finally, here is the paper my team and I submitted to the Astrophysical Journal Letters.
APO Time Resolved Color Photometry of 1I/‘OUMUAMUA (uploaded by DeepSpaceNews’ Gina Smith on Scribd)